The present invention relates to aqueous liquid laundry detergent compositions comprising an emulsion layer.
Liquid laundry detergents are popular with the consumers. It is sometimes desirable to separate various ingredients of the liquid detergent composition. It is also desirable to increase the visual appeal of the detergent package and to provide a unique appearance to be associated by consumers with a particular product. In addition, it is desirable to provide a visual signal to a consumer of the presence of special (e.g., benefit) ingredient in the composition.
EP 116422, EP 175485, GB 1247189, WO 99/47635, Ginn (U.S. Pat. No. 4,348,292), Fuller et al. (U.S. Pat. No. 6,180,587), Swift et al. (U.S. Pat. No. 5,883,065) disclose dual layer liquid cleaning compositions in a bottle or a water insoluble package. The layers are both aqueous and are achieved by employing an electrolyte, which when added to an aqueous surfactant solution, forces the separation of the surfactant from the aqueous phase. The phenomenon of separating an organic component from an aqueous layer, by the addition of a salt (electrolyte) is known as xe2x80x9csalting out.xe2x80x9d The salt increases the ionic character of water and drives the organic, less polar, component away.
Personal cleansing compositions (body wash or shampoo) containing oil are disclosed by e.g. Puvvada et al. (U.S. Pat. No. 5,929,019), Pader, et al., (U.S. Pat. No. 3,533,955), CA951213, Weimer (U.S. Pat. No. 3,718,609), Zabotto et al. (U.S. Pat. No. 5,165,917), and Lyle (U.S. Ser. No. 20010006088). Multiphase aqueous/non-aqueous home care cleaning compositions are disclosed in e.g. WO01/98450, WO02/02731, WO01/21751, WO99/47634, and WO02/04589. Such compositions are shaken before use, to create a temporary emulsion for uniform dispensing and use. Olson et al. (U.S. Pat. No. 3,810,478) discloses a two-phased shampoo composition containing a lower clear polar phase and an upper lotion-like emulsion phase which may be an oil-in-water emulsion.
It is desirable to incorporate oil into laundry detergent compositions for several reasons. Among functional reasons is the ability of the oil to enhance removal of oily stains from fabrics. In addition, oil absorbed onto fabrics provides some degree of softening and anti-wrinkle benefits. Among aesthetic reasons is an increased appeal of a liquid detergent product and to provide a visual signal to a consumer. Unfortunately, if oil is just incorporated into existing laundry detergent compositions, even if the composition is shaken to create a temporary emulsion, the oil layer sticks to the walls of a container during use. This is especially problematic in the field of laundry detergents because containers tend to be larger than the personal care containers and thus the amount of oil on the walls may be significantly detracting from the function and appearance of the product. Thus, it is desirable for functional and aesthetic reasons to provide liquid laundry detergent with an emulsion (milky, lotion-like) layer, wherein oil is present in the form of an emulsion layer with continuous aqueous phase.
The present invention includes an aqueous liquid laundry detergent composition comprising a detergent surfactant (including anionic), an emulsifier with an HLB value below about 8.5; an oil; and an electrolyte in an amount to provide ionic strength indicator of from about 0.55 to about 6.7. The composition separates, upon standing for at most 24 hours at ambient temperature, into at least two layers, one of which is an emulsion with a continuous aqueous phase. The second layer is preferably a transparent composition.
Surprisingly, the emulsion layer that is created has a continuous aqueous phase (i.e. oil-in-water or water-in-oil-in water emulsion), even though the emulsifier that is employed has low HLB typical of water-in-oil emulsifiers, so water-in-oil emulsion would be expected.
The presence of an emulsion layer (which appears as a milky layer) may convey a visual signal of a milder product which may be especially suitable for fine wash or pretreatment laundry product. In addition, the emulsion layer may include oil-soluble or water-insoluble functional ingredients, to preserve the transparency of the second layer, or may include, in the emulsion""s oil phase, water-sensitive ingredients which need to be protected from water.